The instant invention relates to the application of dye images to various types of three dimensional objects, and more particularly to an apparatus and method for applying dye images to three dimensional objects utilizing a sheet or sheets bearing dyes in the mirror images of the desired images, wherein the dyes are of the type which require heat for the application thereof.
Processes for applying disperse dye images to various types of members, wherein dyes are transferred from carrier sheets bearing the dyes in the mirror images of the desired images, are generally known in the printing art. Other processes that are generally related to the art of the present invention are also generally known in the dye sublimation printing field. In general, processes of this type are carried out by first printing an image to be transferred onto a carrier sheet in the reverse orientation from the desired resultant image. The carrier sheet bearing the dye image is placed over an object so that the image is in the desired registration thereon. After the image is placed, heat and pressure are simultaneously applied to the sheet to transfer the dye image from the sheet to the object so that the desired image is permanently produced thereon.
Currently, three-dimensional printing is accomplished as discussed above, using the same techniques and technology developed originally for two-dimensional printing. While this process is generally well known in the prior art, it produces generally unacceptable results when applied to three-dimensional objects. For example, many cellular telephones have replaceable covers and it is desirable to provide replacement covers that bear printed images over the entire surface (front and sides) of the cover. However, when an image is applied using the two dimensional printing technique of the prior art, the image can easily be applied to the front surface of the object, but when the carrier sheet is bent around the contours of the cover it tends to gather and crease resulting in a poor quality transfer image. The drawback in the current technology is that while the paper carrier worked well for flat two-dimensional objects, it does not provide a great degree of flexibility necessary to mold to the required three-dimensional shapes. This arrangement results in uneven and often wrinkled image transfer, as the paper does not firmly and uniformly contact the substrate object as the carrier sheet will bunch and gather at the corners and edges of the object. Further, because of the relative lack of flexibility exhibited by the carrier sheets, it makes the simultaneous application and transfer of a dye image from a carrier sheet to the top and sides of a three-dimensional object very difficult.
In addition, another drawback to the prior art technique is that the infrared heating array used to effect the transfer consists of a flat array of infrared heat lamps. This configuration creates further problems when transferring images onto three dimensional objects because it does not provide uniform heating along the top and sides of the three dimensional object resulting in uneven image transfer along the sides of the object.